Using the various dialog boxes in the Options menu, you can set several options (such as grid lines, color, point protectors, etc.) which change the appearance of the graphs. Use the checkboxes to toggle the options on and off.
 

1. Make sure a graph window is the currently selected window. This is done by single-clicking the graph.

2. Select Graph Options... from the Options menu. You can also double-click on the graph.

3. Choose the options you want to change in the dialog box.

4. Click OK to make the changes take effect.